Use Pinned Gas Blocks Exclusively?

[calicojack]

I am getting tired of set-screw gas blocks. I went to change the dust cover on one of my AR's. Took off the free-float hand guard. Barrel nut was still in the way so I removed it, but, I had to remove the gas tube. I go to drive out the pin holding the gas tube, but the set-screw gas block twists out of place, so I have to remove it as well. Just as well because the dimple for the set screw was not deep enough and needed to be drilled deeper. Fixed that and it seems much better.

So this is one reason I have AR's that use a sight tower; these are staked to the barrel. Now that I have a drill press, I am really thinking about replacing all my set-screw gas blocks with staked blocks. When I took the SOTAR builder's course Chad talked me into a staked pinned gas block for that build and it has been solid.

Any of you guys used staked pinned gas blocks, or do I just need to do a better job of dimpling for my set-screw blocks?

 

[brianns]

You mean pinned gas bocks? I kept thinking staked bolt carrier screws. Lol

If it’s set screws at the gas block, don’t stake those. Screws give you the option to more easily replace it if you want something else. If you find one you like you can probably have it pinned for added measure.

 

[calicojack]

Yeah - pinned. Either pinning the existing gas block that already has the set screws in place or getting a gas block designed to be pinned.

 

[calicojack]

In retrospect - I could have bought a barrel that already had a pinned low pro gas block.

Faxon 10.5" Pencil, 5.56 NATO, Carbine-Length, 4150, Nitride w/ Pinned Gas Block AR-15 Barrel

This 10.5 inch 5.56 AR Barrel with a pinned gas block is manufactured from 4150 CMV steel. Faxon barrels are imbued with quality from the start.

faxonfirearms.com

 

[outrider58]

Some of mine are pinned, some are not. I tend not to pin my later builds, instead, I dimple the barrels to help center the gas port(in some cases) and prevent the block rotating while tapping out the gas tube roll pin. Do you have a bench block? Lay your upper receiver on your bench with the gas block supported in the bench block before you tap out the GB roll pin.

 

[Coehorn]

All of mine are set screws. Loc-Tite 222 Purple on the threads. They've never moved. A tiny amount of heat allows them to be removed easily.

Rinse and Repeat.

 

[Ski169]

I have a few with set screws. One of which was my MK12 that I built at SOTAR. None of them have moved. But I prefer pinned if I can get them. I have moved to using Centurion barrels for a lot of builds and get their low pro gas block with the barrel and have them pin it. As long as the dimples and set screws are done correctly (rockset), they should be fine. So I don’t worry about it. But I’ll stick with pinned if it’s an option and I can get it.

 

[DutchV]

Taper pins are a more solid installation than set screws.

 

[inkd]

I don't use them exclusively. Half of mine have them, half don't.

Ones I've built that I used a dimple jig on have all been fine with Rocksett.

If I had the ability to taper pin them, I would do that though.

 

[SkiPatrolDude]

I have two pinned rifles and the rest are set screw. All have been dimpled, some by the factory and some by me. I’d say if your gas block is twisting from punching out the gas tube roll pin, your set screws may not be torqued correctly or you’re absolutely walloping the gas block.

Alot of the lower to mid-tier brands that use set screws do not dimple from the factory. I bought a CHF PSA upper that was not dimpled. It ran superbly from the factory but I decided to tear it down one day and gave it the ole dimple job. It also lacked grease of any kind on the receiver threads (seen this on a couple of factory Aero builds too).

 

[smokey]

pinned gas blocks are more durable, but set screw/clamp gas blocks are more than solid enough for the job that they need to do. For precision builds, many people prefer a good clamping gas block to put even pressure around the barrel.

It's generally not a good idea to whack on the side of a gas block with a hammer and punch without either removing it or supporting it from the other side.

 

[outrider58]

Some people use coil pins(don't), some use taper pins, and like I, use solid 1/8" SS pins. I personally don't see the need to taper pins. The straight pins stay in quite well. I've seen people al but destroy a milspec FSB trying to bang out a taper pin in the wrong direction.

Just my 2 cents

ETA: Many good gas blocks come with a flat on them for pinning. That makes the job much easier and proper.

 

[Growler215]

I haven't had an issue with set screw gas blocks with a dimpled barrel. I have a "dimpling" jig for this (and a very hard drill bit) for barrels that aren't pre-dimpled. I usually only dimple one hole directly under the gas port. A drop of rocksett for each set screw and gtg. I try to use new gas block set screws if I ever remove a gas block since most gas block set screws are not really supposed to be re-used.

 

[alucard0822]

Nothing wrong with set screw or clamp-on correctly installed in the right application. Proper dimpling is key for set screws, along with torquing and high-temp threadlocker. Easy enough to add a pin if it is a defensive rifle, can cut a flat spot with an end mill if it doesn't already have one, drill it, and hammer a roll pin in. They are nice for lining up a gas block, and roll pins are much easier to swap blocks or barrel nuts compared to taper pins, being it's just added insurance to make sure it can't shift. My precision and competition builds use clamp-on, better seal, easier to replace if needed, and at least on paper it doesn't add asymetric forces to the barrel.

 

[calicojack]

I am intrigued by how many of you use clamp-on gas blocks.

 

[4g64loser]

I am intrigued by how many of you use clamp-on gas blocks.

Yeah. I have a JP clamp type on one rifle.

The ones I have that I'd consider for defense are all taper pinned.

 

[calicojack]

Most of my AR's have MILSPEC front sight towers that are taper pinned, or are PCCs that are n/a. I really only have three AR's that use the set-screws and one additional that is already pinned.